<!DOCTYPE html>
<html lang="zc-CN">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
    <script>
        let day = prompt('请输入一个星期数')
    switch(day) {
        case '星期一' : 
        document.write('monday');
        break
        case '星期二' : 
        document.write('tuesdey');
        break
        case '星期三' : 
        document.write('wednesday');
        break
        case '星期四' : 
        document.write('thursday');
        break
        case '星期五' : 
        document.write('Friday');
        break
        case '星期六' : 
        document.write('saturday');
        break
        case '星期日' : 
        document.write('sunday');
        break
        default:
        document.write('请输入正确的格式');
    }
    </script>
</body>
</html>